The IP addresses usually resolved to a Pacific Rim or European location.

We had installed the Securitycheck extension. However, the offending IPs had to be added manually. That was not a workable solution.

There are a number of commercial and non-commercial Joomla extensions that can help. We tried Adminexile. The extension works by having you set a key and or key/value combination. The end result is that going to www.yoursite.com/administrator no longer takes you to your admin control panel. Rather, it will redirect to whatever page you specify. The default is the home page.

Your new login will look like www.yoursite.com/administrator/index.php?key where key or key=value is what you set in the plugin.

NOTE – It would be a very good idea to back up your site with akeeba backup or other backup tool in the event that something goes wrong. We’ve tried it on a number of sites with no problem.